The retroperitoneal space (retroperitoneum) is the anatomical space (sometimes a potential space) in the abdominal cavity behind (retro) the peritoneum. Description from imgarcade.com. I searched for this on bing.com/images
Psoas muscle abscess and fluid collections are located in the retrofascial space rather than in the retroperitoneal space because the psoas muscles are located posterior to the transversalis fascia, which is the posterior boundary of the retroperitoneum. Ultrasonography is diagnostic in only 60% of cases of psoas abscess, compared with 80% to 100% for CT. Read more: http://radiopaedia.org/articles/psoas-muscle-abscess
Pneumoretroperitoneum - presence of gas within the retroperitoneal space. Typically the air outlines structures like the kidneys, psoas muscles and retroperitoneal portions of the bowel (duodenum, ascending colon, descending colon and rectum). It is almost always due to perforation of a hollow retroperitoneal viscus such as may occur in duodenal ulcer disease, abdominal trauma, diverticulitis, ischemic colitis, colorectal cancer and following endoscopy.
The retroperitoneum is the part of the abdominal cavity that lies between the posterior parietal peritoneum and anterior to the transversalis fascia. It is divided into three spaces by the perirenal fascia and is best visualised using CT or MRI. The three spaces are: anterior pararenal space perirenal space posterior pararenal space http://radiopaedia.org/articles/retroperitoneum
Drawing of the anatomy of the retroperitoneal spaces at the level of the kidneys. The anterior pararenal space (APRS) is located between the parietal peritoneum (PP) and the anterior renal fascia (ARF) and contains the pancreas (Pan), the ascending colon (AC), and the descending colon (DC). The posterior pararenal space (PPRS) is located between the posterior renal fascia (PRF) and the transversalis fascia (TF). The perirenal space (PRS) is located between the anterior renal fascia and the…